fix(init): emit captured logs verbatim; do not rewrite bare CR to LF

Commit 9b54e66 rewrote every bare carriage return in the captured runtime output to
a line feed, intending to render multi-line init tracebacks across lines. But AWS
keeps a bare CR inside a single CloudWatch log event (records split on LF only), and
LocalStack's log ingestion likewise splits on "\n". The conversion therefore wrongly
split any record containing a bare CR into multiple events, breaking the AWS-validated
TestCloudwatchLogs::test_multi_line_prints (a user `print("a\rb")` was emitted as two
events "a" and "b" instead of one event "a\rb").

Emit the runtime output verbatim. Verified: test_multi_line_prints and the full
TestLambdaErrors suite (incl. the runtime-exit/segfault error-reporting tests) are
both green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: joe4dev

cmd/localstack/logs.go

@@ -38,17 +38,13 @@ func (lc *LogCollector) reset() {
 func (lc *LogCollector) getLogs() lsapi.LogResponse {
 	lc.mutex.Lock()
 	defer lc.mutex.Unlock()
-	logs := strings.Join(lc.RuntimeLogs, "")
-	// The runtime emits multi-line records (e.g. an unhandled-init traceback) as a single log
-	// frame with internal newlines replaced by bare carriage returns. AWS renders those back as
-	// line feeds, so convert bare CR to LF while preserving genuine CRLF line endings (which AWS
-	// keeps verbatim, e.g. the LAMBDA_WARNING line).
-	const crlfPlaceholder = "\x00"
-	logs = strings.ReplaceAll(logs, "\r\n", crlfPlaceholder)
-	logs = strings.ReplaceAll(logs, "\r", "\n")
-	logs = strings.ReplaceAll(logs, crlfPlaceholder, "\r\n")
+	// Emit the captured runtime output verbatim. Do NOT rewrite bare carriage returns to line
+	// feeds: AWS keeps a bare CR inside a single CloudWatch log event (it splits records on LF
+	// only), so a user `print("a\rb")` must stay the one event "a\rb". LocalStack's log ingestion
+	// likewise splits on "\n" (see services/lambda_/.../logs.py), so converting CR to LF here
+	// would wrongly split such records — see TestCloudwatchLogs::test_multi_line_prints.
 	response := lsapi.LogResponse{
-		Logs: logs,
+		Logs: strings.Join(lc.RuntimeLogs, ""),
 	}
 	lc.RuntimeLogs = []string{}
 	return response